Method for measuring radical ion flux using a modified Pirani gauge architecture

Abstract

The embodiments disclosed herein include a sensor for detecting radical ion flux. In one embodiment, the sensor comprises a first resistor, where the first resistor comprises a length of wire of a first catalytic composition. In one embodiment, a second resistor is electrically coupled to the first resistor, where the second resistor comprises a length of wire of the first catalytic composition. In one embodiment, the second resistor is coated with a non-catalytic material. In one embodiment, the sensor further comprises a third resistor electrically coupled to the second resistor and a fourth resistor electrically coupled to the first resistor and the third resistor.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 549,703, filed December 13, 2021, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE

[0002] Embodiments relate to the field of semiconductor manufacturing, and in particular to a method and apparatus for measuring radical ion flux using a Pirani gauge. [Background technology]

[0003] The radical ion flux in a plasma processing chamber is responsible for most of the physical changes of the substrate in the plasma processing chamber. However, currently, there are no cost-effective sensors available to detect the radical ion flux in a remote plasma tool or in-situ based plasma processing chamber. Without the ability to measure the radical ion flux, it becomes difficult to implement a plasma source health check, detect process drift, or implement process optimization. Summary of the Invention

[0004] The embodiments disclosed herein include a sensor for detecting radical ion flux. In one embodiment, the sensor comprises a first resistor, where the first resistor comprises a length of wire of a first catalytic composition. In one embodiment, a second resistor is electrically coupled to the first resistor, where the second resistor comprises a length of wire of the first catalytic composition. In one embodiment, the second resistor is coated with a non-catalytic material. In one embodiment, the sensor further comprises a third resistor electrically coupled to the second resistor and a fourth resistor electrically coupled to the first resistor and the third resistor.

[0005] The embodiment may further comprise a plasma processing tool. In one embodiment, the plasma processing tool comprises a chamber and a sensor in the chamber. In one embodiment, the sensor comprises a first catalytic wire and a second catalytic wire, where the second catalytic wire is covered by a non-catalytic material.

[0006] The embodiment may further comprise a plasma processing tool. In one embodiment, the plasma processing tool comprises a remote plasma source and a chamber, where the chamber is fluidly coupled to the remote plasma source. In one embodiment, the tool further comprises a support in the chamber for securing a substrate, an exhaust fluidly coupled to the chamber, and a first radical ion sensor in the chamber. In one embodiment, a second radical ion sensor is in the remote plasma source and a third radical ion sensor is in the exhaust. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a sensor for detecting radical ion flux, according to one embodiment. [Diagram 2] 1 is a graph of resistance versus temperature for a platinum wire, according to one embodiment. [Diagram 3] 1 is a graph of the temperature of a wire in a plasma chamber over various plasma settings, according to one embodiment. [Figure 4A] FIG. 2 is a plan view of a substrate with radical ion flux sensors in each quadrant and in the center of the substrate according to one embodiment. [Figure 4B] FIG. 2 is a plan view of a substrate with multiple radical ion flux sensors across its surface, according to one embodiment. [Figure 4C] FIG. 2 is a plan view of a substrate with multiple radical ion flux sensors in a line pattern across the surface of the substrate, according to one embodiment. [Diagram 5] FIG. 1 is a perspective view of a processing chamber with a radical ion flux sensor at the end of a probe that extends above a substrate in the chamber, according to one embodiment. [Figure 6A]FIG. 2 is a cross-sectional view of a plasma processing chamber with radical ion flux sensors in the main chamber and along the exhaust line according to one embodiment. [Figure 6B] FIG. 2 is a cross-sectional view of a plasma processing chamber with a remote plasma source and multiple radical ion flux sensors according to one embodiment. [Figure 7] FIG. 1 illustrates a block diagram of an exemplary computer system that may be used in conjunction with a processing tool, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The system described herein includes a method and apparatus for measuring radical ion flux using a Pirani gauge-based device. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent to one of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known aspects will not be described in detail in order not to unnecessarily obscure the embodiments. Moreover, it should be understood that the various embodiments shown in the accompanying drawings are illustrative representations and are not necessarily drawn to scale.

[0009] As mentioned above, there is currently a lack of a cost-effective sensor for measuring radical ion flux in a plasma processing chamber. Therefore, embodiments disclosed herein include a sensor that can be easily integrated into a plasma processing chamber or provided on a substrate that is inserted into the processing chamber. In certain embodiments, the sensor can be a modified Pirani gauge sensor. For example, the sensor can include a first wire and a second wire. The first wire is exposed and the second wire is surrounded by an insulating layer. In one embodiment, the first wire and the second wire can be a catalytic material, such as platinum or nickel. Since the first wire is exposed, the catalytic material promotes recombination of radical ions, which leads to a temperature change of the first wire. The temperature change corresponds to an increase in the resistance of the first wire, and the resistance change can be measured directly. Since the second wire is covered by a non-catalytic material, the second wire can act as a reference. Moreover, it should be appreciated that the dimensions (e.g., surface area, length, mass) of the second wire are substantially equal to the dimensions of the first wire, and thus the difference between the temperature of the first wire and the temperature of the second wire can be correlated to the radical ion flux in the chamber.

[0010] In one embodiment, the sensor is provided on a substrate that is inserted into the plasma chamber. For example, multiple sensors can be fabricated on the substrate to provide spatial resolution of the radical ion flux in the plasma chamber. In one embodiment, the sensor can be extended over the substrate with a probe architecture. Additionally, the sensor can be provided throughout different parts of the plasma chamber. For example, the sensor can be located downstream in the exhaust line of the chamber, in a remote plasma chamber, or adjacent to the outlet (e.g., the process chamber side of the remote plasma chamber / source).

[0011] In one embodiment, the use of a radical ion flux sensor enables several benefits in chamber monitoring. In some embodiments, such a sensor may be used as part of a plasma source (e.g., either remote or in situ) health check solution. In other embodiments, such a sensor may be used to aid in process drift detection. Other embodiments may use the sensor to implement process optimization.

[0012] Referring now to FIG. 1, a schematic diagram of a sensor 100 is shown, according to one embodiment. In one embodiment, the sensor 100 comprises a Wheatstone bridge architecture. That is, a set of four resistors 110, 112, 114, and 116 may be electrically coupled to each other in a ring architecture. In one embodiment, the first resistor 110 and the second resistor 112 may be formed by catalytic wires. For example, the catalytic wire may be a material that supports the recombination of radical ions. For example, for hydrogen and oxygen radical ions, the first catalytic wire may include platinum or nickel. Of course, plasmas with different nuclear species may include other types of catalytic wires.

[0013] In one embodiment, the first resistor 110 and the second resistor 112 may be substantially the same as each other. The difference between the first resistor 110 and the second resistor 112 is that the second resistor 112 is covered by a non-catalytic material 115. For example, the second resistor 112 may be coated with a material 115 comprising silicon and oxygen (e.g., SiO2) or aluminum and oxygen (e.g., Al2O3). In one embodiment, the coating 115 is deposited on the second resistor 112 using any suitable deposition process. In a particular embodiment, the coating 115 is provided on the second resistor 112 using an atomic layer deposition (ALD) process. In one embodiment, the ALD coating may cover all wetted parts except for the catalytic platinum / nickel resistor components of the first resistor 110. This minimizes the response of the passive components of the second resistor 112 as well as the reference platinum / nickel sensor. To fabricate such a structure, all wetted components can be coated with an ALD process and a film can be etched from the catalytic platinum / nickel first resistor 110.

[0014] In one embodiment, the catalytic wire is heated to a temperature. The voltage required to do this is monitored using a Wheatstone bridge architecture. The change in voltage correlates to the temperature change of the catalytic wire induced by radical ion recombination.

[0015] Referring now to FIG. 2, a graph of temperature versus resistance of a catalytic wire is shown, according to one embodiment. As shown, there is a linear relationship between temperature and resistance. Thus, a change in resistance may be measured to detect a change in temperature. In the illustrated embodiment, the catalytic material shown in the graph is platinum. However, it should be appreciated that a relationship between temperature and resistance may also be provided when other catalytic materials are used, such as nickel. While platinum has a linear relationship, nickel may have a non-linear relationship, which may require application of a calibration curve to such an embodiment.

[0016] Referring now to FIG. 3, a graph of the temperature of the first catalytic wire 110 over time is shown according to one embodiment. Until about 625 seconds, the plasma is only an argon plasma. Thus, there is no heating due to radical ion recombination. For example, the temperature of the first catalytic wire 110 may be about 100° C. At about 625 seconds, a processing gas such as oxygen and hydrogen may be added to the chamber. The processing gas is ionized to form radical ion species. As shown in the first step 321, the temperature of the first catalytic wire 110 increases. A power increase from 1 kW in the first step 321 to 2 kW in the second step 322 results in an increase in temperature. Furthermore, an increase to 3 kW in the third step 323 results in yet another increase in temperature. Thus, the change in temperature of the catalytic wire 110 may be correlated to a change in radical ion flux. In one embodiment, the catalytic wire 110 is configured to provide a rapid change in temperature. This is made possible by having a wire with a low mass. Thus, rapid detection of changes in radical ion flux is possible.

[0017] 4A-4C, a series of plan views depicting various architectures utilizing a radical ion flux sensor according to different embodiments are shown. In one embodiment, the sensor is provided on a substrate. The substrate may be a semiconductor substrate, such as a silicon substrate. In other embodiments, the substrate may be glass or any other type of substrate common to semiconductor manufacturing processes.

[0018] 4A, a plan view of a sensor device 450 is shown, according to one embodiment. In one embodiment, the sensor device 450 includes a plurality of radical ion flux sensors 400 dispersed over a surface of a substrate 451. A ~400 E For example, the sensor 400 A ~400 D may each be in a different quadrant of the substrate 451, and the sensor 400 Ecan be at the center of the substrate 451. Thus, radical ion flux readings can be provided for a number of different locations within the chamber.

[0019] In one embodiment, the sensor 400 A ~400 E The electrical circuitry for the sensor 400 may be fabricated as part of the substrate 451. A ~400 E may be separate sensors mounted on the substrate 451. In some embodiments, the sensor 400 A ~400 E Data from may be stored in memory fabricated on or attached to the substrate 451. Alternatively, connections from the substrate to devices external to the processing chamber may be made through vacuum feedthroughs or through a thin layer of tape that passes over an O-ring in the chamber.

[0020] In one embodiment, each sensor 400 A ~400 E may include a first catalytic wire that is exposed to light and a second catalytic wire that is coated with a non-catalytic material. That is, each sensor may include a wire for sensing radical ion flux and a wire for acting as a temperature reference. In such an embodiment, the first catalytic wire and the second catalytic wire have a one-to-one ratio. In other embodiments, each sensor 400 may include a first catalytic wire that is exposed to light and a second catalytic wire that is coated with a non-catalytic material. A ~400 E may include a first catalytic wire, and each sensor 400 A ~400 E may not include a second coated catalytic wire, i.e., the first catalytic wire and the second coated wire may not have a one to one ratio in some embodiments.

[0021] 4B, a plan view of a sensor device 450 is shown, according to an additional embodiment. As shown, a plurality of sensors 400 are arranged across a surface of a substrate 451. Such an embodiment may be referred to as a contour sensor 400 layout. In the illustrated embodiment, 49 sensors 400 are used. However, it should be appreciated that any number of sensors 400 may be used to provide a desired level of resolution.

[0022] In one embodiment, each of the sensors 400 may include an exposed first catalytic wire and a second catalytic wire covered with a coating. Such an embodiment may be referred to as a one-to-one architecture. In other embodiments, each sensor 400 may include an exposed first catalytic wire, and fewer than all of the sensors 400 may have a reference wire (in other words, a coated catalytic wire). In such an embodiment, the first catalytic wire may have a many-to-one ratio with the coated second catalytic wire.

[0023] 4A, electronic circuitry may be mounted on the substrate 451 to operate to store data from the sensor 400. In other embodiments, wires may pass through a vacuum feedthrough or across an O-ring. The sensor 400 may be a separate structure attached to the substrate 451. In other embodiments, the sensor 400 may be integrated as part of the substrate 451.

[0024] 4C, a plan view of a sensor device 450 is shown in accordance with an additional embodiment. As shown, a plurality of sensors 400 are arranged in a line across a surface of a substrate 451. Such an embodiment may be referred to as a line scan layout. In the illustrated embodiment, eleven sensors 400 are used. However, it should be appreciated that any number of sensors 400 may be used to provide a desired level of resolution.

[0025] In one embodiment, each of the sensors 400 may include an exposed first catalytic wire and a second catalytic wire covered with a coating. Such an embodiment may be referred to as a one-to-one architecture. In other embodiments, each sensor 400 may include an exposed first catalytic wire, and fewer than all of the sensors 400 may have a reference wire (in other words, a coated catalytic wire). In such an embodiment, the first catalytic wire may have a many-to-one ratio with the coated second catalytic wire.

[0026] 4A, electronic circuitry may be mounted on the substrate 451 to operate to store data from the sensor 400. In other embodiments, wires may pass through vacuum feedthroughs or across O-rings. The sensor 400 may be a separate structure attached to the substrate 451. In other embodiments, the sensor 400 may be integrated as part of the substrate 451.

[0027] 5, a perspective view of a portion of a plasma chamber 560 is shown, according to one embodiment. In one embodiment, a substrate 561 is supported in the chamber 560. For example, the substrate 561 may be a semiconductor substrate, such as a silicon wafer. An edge ring 563 may surround the periphery of the substrate 561. A chamber wall 564 may surround the periphery of the edge ring 563.

[0028] In one embodiment, the probe 562 may be attached to the edge ring 563 and extend over the surface of the substrate 561. At the end of the probe 562 above the substrate 561, a catalytic wire 510 may be provided. The catalytic wire 510 may be a platinum wire or a nickel wire in some embodiments. In one embodiment, the probe 562 may further comprise a second catalytic wire (not shown) coated with a non-catalytic layer, such as SiO2 or Al2O3. The coated second catalytic wire may alternatively be provided on a different probe (not shown in FIG. 5). Although shown as extending over the surface of the substrate 561, it should be appreciated that the probe 562 may not extend over the surface of the substrate 561 during processing, as this may result in shadowing and add potential for metal contamination. Alternatively, the probe 562 may be placed on the edge ring 563. Additionally, it should be appreciated that there may be multiple sensors around the edge ring 563.

[0029] In one embodiment, the probe 562 may be coupled to an external computing system that stores data and controls the sensors. One or more wires at the end of the probe attached to the edge ring 563 may pass through a vacuum feedthrough through the chamber wall 564 or over an O-ring (not shown) between the chamber lid (not shown) and the chamber wall 564.

[0030] In the illustrated embodiment, a single probe 562 is shown for simplicity. However, it should be appreciated that any number of probes 562 may be used to provide a desired spatial resolution of the radical ion flux. In yet another embodiment, the probe 562 may be scanned over the surface of the substrate 561 to provide a spatial chart of the radical ion flux for a given plasma process. For example, the probe 562 may be a telescoping probe and be capable of scanning back and forth across the substrate 561 in a windshield wiper-like pattern. Additionally, the probe 562 may be scanned linearly across the substrate 561 and / or chamber 560.

[0031] 6A and 6B, cross-sectional views of a plasma processing tool are shown, according to various embodiments. The plasma processing tool 660 can be used to implement one or more plasma processes on a substrate 661 held in a chamber 664.

[0032] 6A, a cross-sectional view of a plasma processing tool 660 is shown, according to one embodiment. In one embodiment, the plasma processing tool 660 includes a chamber 664 having a lid 665. Processing gases may flow into the chamber 664 (e.g., through the lid 665), and a plasma may be struck in the chamber 664 between the lid 665 and a substrate 661. In one embodiment, the substrate 661 may be a wafer, such as a silicon wafer or any semiconductor substrate. In one embodiment, the substrate 661 may be supported by a pedestal 671. The pedestal 671 may be a temperature controlled component that secures the substrate 661 (e.g., using a vacuum chucking process, an electrostatic chucking process, etc.).

[0033] In one embodiment, the chamber 664 may be held at a vacuum pressure (e.g., below atmospheric pressure) with the aid of an exhaust system 666. The exhaust system 666 may include one or more pumps (not shown) configured to reduce the pressure inside the chamber 664.

[0034] In one embodiment, multiple sensors 600 may be provided in a plasma processing tool 660. In the embodiment shown in FIG. 6A, a first sensor 600 A is provided on the surface of the substrate 661. A The sensor 600 may include a first catalytic wire and a second catalytic wire covered with a non-catalytic coating. A can be one of many sensors provided on substrate 661. For example, a sensor 600 can be provided on each quadrant of substrate 661 (as in the embodiment shown in FIG. 4A), a sensor 600 can be provided as a contour map architecture (as in the embodiment shown in FIG. 4B), or a sensor 600 can be provided in a line pattern (as in the embodiment shown in FIG. 4C). A may be provided above the substrate 661. For example, a probe (not shown) may extend above the top surface of the substrate 661, and the sensor 600 A However, the sensor 600 may be at the end of the probe. A It should be appreciated that the may only need to be above the substrate holder during setup and / or health checks, and may be removed from above the substrate 661 during processing of the substrate 661.

[0035] In one embodiment, the second sensor 600 B The second sensor 600 may be provided along the exhaust line 666. B The second sensor 600 may include a first catalytic wire and a second catalytic wire coated with a non-catalytic coating. B may include a sensor architecture that is similar to that shown in Figure 1. Thus, radical ion flux may be measured at a location downstream of chamber 664.

[0036] 6B, a cross-sectional view of a plasma processing tool 660 is shown in accordance with an additional embodiment. In one embodiment, the plasma processing tool 660 includes a chamber 664 having a lid 665. In one embodiment, a remote plasma source 672 is coupled to the chamber 664. A plasma 673 may be generated in the remote plasma source 672 and flow through a pipe 674 to the lid 665. The plasma 673 may be dispersed through the lid 665 (which may be a baffle in some embodiments) into the chamber 664.

[0037] In one embodiment, the substrate 661 may be supported by a pedestal 671. The pedestal 671 may be a temperature controlled component that secures the substrate 661 (e.g., using a vacuum chucking process, an electrostatic chucking process, etc.). In one embodiment, the substrate 661 may be a wafer, such as a silicon wafer or any semiconductor substrate.

[0038] In one embodiment, the chamber 664 may be held at a vacuum pressure (e.g., below atmospheric pressure) with the aid of an exhaust system 666. The exhaust system 666 may include one or more pumps (not shown) configured to reduce the pressure inside the chamber 664.

[0039] In one embodiment, multiple sensors 600 are provided in a plasma processing tool 660. In the embodiment shown in FIG. 6B, a first sensor 600 A is provided on the surface of the substrate 661. A The sensor 600 may include a first catalytic wire and a second catalytic wire covered with a non-catalytic coating. Acan be one of many sensors provided on substrate 661. For example, a sensor 600 can be provided on each quadrant of substrate 661 (as in the embodiment shown in FIG. 4A), a sensor 600 can be provided as a contour map architecture (as in the embodiment shown in FIG. 4B), or a sensor 600 can be provided in a line pattern (as in the embodiment shown in FIG. 4C). A may be provided above the substrate 661. For example, a probe (not shown) may extend above the top surface of the substrate 661, and the sensor 600 A may be at the end of the probe.

[0040] In one embodiment, the second sensor 600 B The second sensor 600 may be provided along the exhaust line 666. B The second sensor 600 may include a first catalytic wire and a second catalytic wire coated with a non-catalytic coating. B may include a sensor architecture that is similar to that shown in Figure 1. Thus, radical ion flux may be measured at a location downstream of chamber 664.

[0041] In one embodiment, the third sensor 600 C The third sensor 600 may be disposed between the remote plasma source 672 and the lid 665. C may be provided along the pipe 674. In other embodiments, a third sensor 600 C may be provided in the remote plasma source 672. C The inclusion of allows the radical ion flux to be read upstream and downstream of chamber 664.

[0042] Referring now to FIG. 7, a block diagram of an exemplary computer system 700 of a processing tool is illustrated, according to one embodiment. In one embodiment, the computer system 700 is coupled to the processing tool and controls processing in the processing tool. The computer system 700 may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The computer system 700 may operate in the capacity of a server or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 700 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a cellular phone, a web appliance, a server, a network router, a switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by the machine. Additionally, although only a single machine is illustrated for computer system 700, the term "machine" should also be interpreted to include any collection of machines (e.g., computers) that individually or together execute a set (or sets) of instructions to perform any one or more of the methodologies described herein.

[0043] The computer system 700 may include a computer program product or software 722 having a non-transitory machine-readable medium having instructions stored thereon, which may be used to program the computer system 700 (or other electronic devices) to perform processes according to the embodiments. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., computer) readable storage medium (e.g., read-only memory ("ROM"), random access memory ("RAM"), magnetic disk storage media, optical storage media, flash memory devices, etc.), a machine (e.g., computer) readable transmission medium (electrical, optical, acoustic or other form of propagated signal (e.g., infrared signal, digital signal, etc.)), etc.

[0044] In one embodiment, computer system 700 includes a system processor 702, a main memory 704 (e.g., read only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 706 (e.g., flash memory, static random access memory (SRAM), etc.), and a secondary memory 718 (e.g., a data storage device), which communicate with each other via a bus 730.

[0045] The system processor 702 represents one or more general-purpose processing devices, such as a microsystem processor, a central processing unit, etc. More specifically, the system processor may be a complex instruction set computing (CISC) microsystem processor, a reduced instruction set computing (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor implementing other instruction sets, or a system processor implementing a combination of instruction sets. The system processor 702 may also be one or more special-purpose processing devices, such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal system processor (DSP), a network system processor, etc. The system processor 702 is configured to execute processing logic 726 for performing the operations described herein.

[0046] The computer system 700 may further include a system network interface device 708 for communicating with other devices or machines. The computer system 700 may also include a video display unit 710 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 712 (e.g., a keyboard), a cursor control device 714 (e.g., a mouse), and a signal generating device 716 (e.g., a speaker).

[0047] The secondary memory 718 may include a machine-accessible storage medium 732 (or more specifically, a computer-readable storage medium) on which is stored one or more sets of instructions (e.g., software 722) embodying any one or more of the methodologies or functions described herein. The software 722 may also reside, completely or at least partially, within the main memory 704 and / or within the system processor 702 during its execution by the computer system 700, with the main memory 704 and the system processor 702 also constituting machine-readable storage media. The software 722 may further be transmitted or received over the network 720 via the system network interface device 708. In one embodiment, the network interface device 708 may operate using RF, optical, acoustic, or inductive coupling.

[0048] Although the machine-accessible storage medium 732 is shown in the exemplary embodiment to be a single medium, the term "machine-readable storage medium" should be interpreted to include a single medium or multiple media (e.g., centralized or distributed databases and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be interpreted to include any medium that is capable of storing or encoding a set of instructions for execution by a machine, causing the machine to perform any one or more of the methodologies. The term "machine-readable storage medium" should therefore be interpreted to include, but is not limited to, solid-state memories, and optical and magnetic media.

[0049] In the foregoing specification, specific exemplary embodiments have been described. It will be apparent that various modifications may be made thereto without departing from the scope of the following claims. The specification and drawings are therefore to be regarded in an illustrative rather than a restrictive sense.

Claims

1. a first temperature sensor comprising a first surface of a first catalyst composition; a second temperature sensor having a second surface, the second surface being coated with a non-catalytic material; and A sensor for detecting radical flux comprising:

2. The sensor of claim 1 , wherein the first temperature sensor and the second temperature sensor are connected together in a Wheatstone bridge configuration.

3. The sensor of claim 2 , wherein a change in voltage across the Wheatstone bridge correlates to a temperature change in the first temperature sensor induced by radical ion recombination.

4. The sensor of claim 1 , wherein the first catalytic composition comprises platinum.

5. The sensor of claim 1 , wherein the first catalyst composition comprises nickel.

6. The sensor of claim 1 , wherein the non-catalytic material comprises silicon and oxygen.

7. The sensor of claim 1 , wherein the non-catalytic material comprises aluminum and oxygen.

8. The sensor of claim 1 , wherein the sensor is integrated onto a substrate that is insertable into a plasma chamber.

9. The sensor of claim 1 , wherein the sensor is mounted on the end of a probe within a plasma chamber.

10. The sensor of claim 1 , wherein the first temperature sensor and the second temperature sensor are resistors or thermocouples.

11. A chamber; A sensor in the chamber, the sensor comprising: a first catalytic surface; and a second surface, the second surface being covered with a non-catalytic material; and A sensor and A plasma processing tool comprising:

12. The plasma processing tool of claim 11 , wherein the sensor is on a probe that extends above a support for holding a substrate.

13. The plasma processing tool of claim 11 , wherein the sensor is in an exhaust line coupled between the chamber and a vacuum pump.

14. The plasma processing tool of claim 11 , further comprising a remote plasma source, the sensor being disposed within the remote plasma source.

15. The plasma processing tool of claim 11 , wherein the first catalytic surface and the second surface comprise platinum.

16. The plasma processing tool of claim 11 , wherein the first catalytic surface and the second surface comprise nickel.

17. The plasma processing tool of claim 11 , wherein the non-catalytic material comprises silicon and oxygen.

18. The plasma processing tool of claim 11 , wherein the non-catalytic material comprises aluminum and oxygen.

19. A remote plasma source; a chamber, the chamber fluidly coupled to the remote plasma source; a support in said chamber for fixing a substrate; an exhaust fluidly coupled to the chamber; a first radical sensor in the chamber; a second radical sensor in the remote plasma source; a third radical sensor in the exhaust gas; A plasma processing tool comprising:

20. The first radical sensor, the second radical sensor, and the third radical sensor are a first catalytic surface; and a second surface, the second surface being covered with a non-catalytic material; and The plasma processing tool of claim 19 , comprising:

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